Abstract

Introduction: Recurrences of atrial fibrillation (AF) can be reduced by ablation of atrial sources. This study presents a new methodology based on causal analysis that allows identifying these dominant areas during AF.
Methods: Causal relations were estimated for intracardiac recordings obtained by using a multipolar spiral catheter in
four paroxysmal AF patients during electrical pacing and atrial fibrillation. Causal measurements were summarized into a map highlighting the location of the electrical sources and the dominant propagation directions for each region.
Results: During electrical stimulation, the propagation patterns obtained by causal analysis were consistent with the location of the pacing catheter. Propagation patterns detected during AF presented temporal variability, but a dominant direction accounted for significantly more propagations than other possible directions (49±15% vs. 14±13% or less, p<0.01, Panel A). Combination of sequentially measured causal relations at different atrial sites that cover the entire atria allow representing the global propagation pattern and identifying AF sources. In panel B, sample case of identification of the dominant site on the left PVs in a patient in which AF terminated after ablation of the LIPV.
Conclusions: Causal methodology provided a consistent estimation of dominant propagation patterns during electrical
pacing and AF. Causality analysis allows the identification of fibrillatory sources in the atria and can serve as guidance for ablation procedures.